Our primary aim was to describe migration of the Exeter stem with a 32 mm head on highly crosslinked polyethylene and whether this is influenced by age. Our secondary aims were to assess functional outcome, satisfaction, activity, and bone mineral density (BMD) according to age. A prospective cohort study was conducted. Patients were recruited into three age groups: less than 65 years (n = 65), 65 to 74 years (n = 68), and 75 years and older (n = 67). There were 200 patients enrolled in the study, of whom 115 were female and 85 were male, with a mean age of 69.9 years (sd 9.5, 42 to 92). They were assessed preoperatively, and at three, 12 and, 24 months postoperatively. Stem migration was assessed using Einzel-Bild-Röntgen-Analyse (EBRA). Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Harris Hip Score (HHS), Hip Disability and Osteoarthritis Outcome Score (HOOS), EuroQol-5 domains questionnaire (EQ-5D), short form-36 questionnaire (SF-36,) and patient satisfaction were used to assess outcome. The Lower Extremity Activity Scale (LEAS), Timed Up and Go (TUG) test, and activPAL monitor (energy expelled, time lying/standing/walking and step count) were used to assess activity. The BMD was assessed in Gruen and Charnley zones.Objectives
Patients and Methods
Previous studies have suggested that metal-on-metal (MoM) Pinnacle (DePuy Synthes, Warsaw, Indiana) hip arthroplasties implanted after 2006 exhibit higher failure rates. This was attributed to the production of implants with reduced diametrical clearances between their bearing surfaces, which, it was speculated, were outside manufacturing tolerances. This study aimed to better understand the performance of Pinnacle Systems manufactured before and after this event. A total of 92 retrieved MoM Pinnacle hips were analyzed, of which 45 were implanted before 2007, and 47 from 2007 onwards. The ‘pre-2007’ group contained 45 implants retrieved from 21 male and 24 female patients, with a median age of 61.3 years (interquartile range (IQR) 57.1 to 65.5); the ‘2007 onwards’ group contained 47 implants retrieved from 19 male and 28 female patients, with a median age of 61.8 years (IQR 58.5 to 67.8). The volume of material lost from their bearing and taper surfaces was measured using coordinate and roundness measuring machines. These outcomes were then compared statistically using linear regression models, adjusting for potentially confounding factors.Objectives
Methods
The aim of this study was to determine whether there is a difference
in the rate of wear between acetabular components positioned within
and outside the ‘safe zones’ of anteversion and inclination angle. We reviewed 100 hips in 94 patients who had undergone primary
total hip arthroplasty (THA) at least ten years previously. Patients
all had the same type of acetabular component with a bearing couple
which consisted of a 28 mm cobalt-chromium head on a highly crosslinked
polyethylene (HXLPE) liner. A supine radiostereometric analysis
(RSA) examination was carried out which acquired anteroposterior
(AP) and lateral paired images. Acetabular component anteversion
and inclination angles were measured as well as total femoral head
penetration, which was divided by the length of implantation to
determine the rate of polyethylene wear.Aims
Patients and Methods
We sought to establish whether an oxidised zirconium (OxZr) femoral
component causes less loss of polyethylene volume than a cobalt
alloy (CoCr) femoral component in total knee arthroplasty. A total of 20 retrieved tibial inserts that had articulated with
OxZr components were matched with 20 inserts from CoCr articulations
for patient age, body mass index, length of implantation, and revision
diagnosis. Changes in dimensions of the articular surfaces were compared
with those of pristine inserts using laser scanning. The differences
in volume between the retrieved and pristine surfaces of the two
groups were calculated and compared.Aims
Materials and Methods
Wear of polyethylene inserts plays an important role in failure
of total knee replacement and can be monitored Before revision, the minimum joint space width values and their
locations on the insert were measured in 15 fully weight-bearing
radiographs. These measurements were compared with the actual minimum
thickness values and locations of the retrieved tibial inserts after
revision. Introduction
Method
Squeaking arising from a ceramic-on-ceramic (CoC)
total hip replacement (THR) may cause patient concern and in some
cases causes patients to seek revision surgery. We performed a meta-analysis
to determine the incidence of squeaking and the incidence of revision
surgery for squeaking. A total of 43 studies including 16 828 CoC
THR that reported squeaking, or revision for squeaking, were entered
into the analysis. The incidence of squeaking was 4.2% and the incidence
of revision for squeaking was 0.2%. The incidence of squeaking in
patients receiving the Accolade femoral stem was 8.3%, and the incidence
of revision for squeaking in these patients was 1.3%. Cite this article:
Wear debris released from bearing surfaces has been shown to
provoke negative immune responses in the recipient. Excessive wear
has been linked to early failure of prostheses. Analysis using coordinate
measuring machines (CMMs) can provide estimates of total volumetric
material loss of explanted prostheses and can help to understand
device failure. The accuracy of volumetric testing has been debated,
with some investigators stating that only protocols involving hundreds
of thousands of measurement points are sufficient. We looked to
examine this assumption and to apply the findings to the clinical
arena. We examined the effects on the calculated material loss from
a ceramic femoral head when different CMM scanning parameters were
used. Calculated wear volumes were compared with gold standard gravimetric
tests in a blinded study. Objectives
Methods
We reviewed the literature on the currently available
choices of bearing surface in total hip replacement (THR). We present
a detailed description of the properties of articulating surfaces
review the understanding of the advantages and disadvantages of
existing bearing couples. Recent technological developments in the
field of polyethylene and ceramics have altered the risk of fracture
and the rate of wear, although the use of metal-on-metal bearings has
largely fallen out of favour, owing to concerns about reactions
to metal debris. As expected, all bearing surface combinations have
advantages and disadvantages. A patient-based approach is recommended,
balancing the risks of different options against an individual’s
functional demands. Cite this article:
The purpose of this study was to compare the
amount of acetabular bone removed during hip resurfacing (HR) and cementless
total hip replacement (THR), after controlling for the diameter
of the patient’s native femoral head. Based on a power analysis,
64 consecutive patients (68 hips) undergoing HR or THR were prospectively
enrolled in the study. The following data were recorded intra-operatively:
the diameter of the native femoral head, the largest reamer used,
the final size of the acetabular component, the size of the prosthetic
femoral head and whether a decision was made to increase the size
of the acetabular component in order to accommodate a larger prosthetic femoral
head. Results were compared using two-sided, independent samples
Student’s
The popularity of cementless total hip replacement
(THR) has surpassed cemented THR in England and Wales. This retrospective
cohort study records survival time to revision following primary
cementless THR with the most common combination (accounting for
almost a third of all cementless THRs), and explores risk factors independently
associated with failure, using data from the National Joint Registry
for England and Wales. Patients with osteoarthritis who had a DePuy
Corail/Pinnacle THR implanted between the establishment of the registry
in 2003 and 31 December 2010 were included within analyses. There
were 35 386 procedures. Cox proportional hazard models were used
to analyse the extent to which the risk of revision was related
to patient, surgeon and implant covariates. The overall rate of
revision at five years was 2.4% (99% confidence interval 2.02 to
2.79). In the final adjusted model, we found that the risk of revision
was significantly higher in patients receiving metal-on-metal (MoM:
hazard ratio (HR) 1.93, p <
0.001) and ceramic-on-ceramic bearings
(CoC: HR 1.55, p = 0.003) compared with the best performing bearing
(metal-on-polyethylene). The risk of revision was also greater for
smaller femoral stems (sizes 8 to 10: HR 1.82, p <
0.001) compared
with mid-range sizes. In a secondary analysis of only patients where body
mass index (BMI) data were available (n = 17 166), BMI ≥ 30 kg/m2 significantly
increased the risk of revision (HR 1.55, p = 0.002). The influence
of the bearing on the risk of revision remained significant (MoM:
HR 2.19, p <
0.001; CoC: HR 2.09,
p = 0.001). The risk of revision was independent of age, gender,
head size and offset, shell, liner and stem type, and surgeon characteristics. We found significant differences in failure between bearing surfaces
and femoral stem size after adjustment for a range of covariates
in a large cohort of single-brand cementless THRs. In this study
of procedures performed since 2003, hard bearings had significantly
higher rates of revision, but we found no evidence that head size
had an effect. Patient characteristics, such as BMI and American
Society of Anesthesiologists grade, also influence the survival
of cementless components. Cite this article:
In this prospective study we studied the effect
of the inclination angle of the acetabular component on polyethylene wear
and component migration in cemented acetabular sockets using radiostereometric
analysis. A total of 120 patients received either a cemented Reflection
All-Poly ultra-high-molecular-weight polyethylene or a cemented
Reflection All-Poly highly cross-linked polyethylene acetabular
component, combined with either cobalt–chrome or Oxinium femoral
heads. Femoral head penetration and migration of the acetabular
component were assessed with repeated radiostereometric analysis
for two years. The inclination angle was measured on a standard
post-operative anteroposterior pelvic radiograph. Linear regression
analysis was used to determine the relationship between the inclination
angle and femoral head penetration and migration of the acetabular component. We found no relationship between the inclination angle and penetration
of the femoral head at two years’ follow-up (p = 0.9). Similarly,
our data failed to reveal any statistically significant correlation
between inclination angle and migration of these cemented acetabular
components (p = 0.07 to p = 0.9).
Retrieval studies of total hip replacements with highly cross-linked ultra-high-molecular-weight polyethylene liners have shown much less surface damage than with conventional ultra-high-molecular-weight polyethylene liners. A recent revision hip replacement for recurrent dislocation undertaken after only five months revealed a highly cross-linked polyethylene liner with a large area of visible delamination. In order to determine the cause of this unusual surface damage, we analysed the bearing surfaces of the cobalt-chromium femoral head and the acetabular liner with scanning electron microscopy, energy dispersive x-ray spectroscopy and optical profilometry. We concluded that the cobalt-chromium modular femoral head had scraped against the titanium acetabular shell during the course of the dislocations and had not only roughened the surface of the femoral head but also transferred deposits of titanium onto it. The largest deposits were 1.6 μm to 4.3 μm proud of the surrounding surface and could lead to increased stresses in the acetabular liner and therefore cause accelerated wear and damage. This case illustrates that dislocations can leave titanium deposits on cobalt-chromium femoral heads and that highly cross-linked ultra-high-molecular-weight polyethylene remains susceptible to surface damage.
We report the clinical and radiological outcome at ten years of 104 primary total hip replacements (100 patients) using the Metasul metal-on-metal bearing. Of these, 52 had a cemented Stuehmer-Weber polyethylene acetabular component with a Metasul bearing and 52 had an uncemented Allofit acetabular component with a Metasul liner. A total of 15 patients (16 hips) died before their follow-up at ten years and three were lost to follow-up. The study group therefore comprised 82 patients (85 hips). The mean Oxford score at ten years was 20.7 (12 to 42). Six of 85 hips required revision surgery. One was performed because of infection, one for aseptic loosening of the acetabular component and four because of unexplained pain. Histological examination showed an aseptic lymphocytic vasculitis associated lesion-type tissue response in two of these. Continued follow-up is advocated in order to monitor the long-term performance of the Metasul bearing and tissue responses to metal debris.
This study reviewed the results of a cementless anatomical femoral component to give immediate post-operative stability, and with a narrow distal section in order not to contact the femoral cortex in the diaphysis, ensuring exclusively metaphyseal loading. A total of 471 patients (601 hips) who had a total hip replacement between March 1995 and February 2002 were included in the study. There were 297 men and 174 women. The mean age at the time of operation was 52.7 years (28 to 63). Clinical and radiological evaluation were performed at each follow-up. Bone densitometry was carried out on all patients two weeks after operation and at the final follow-up examination. The mean follow-up was 8.8 years (5 to 12). The mean pre-operative Harris hip score was 41 points (16 to 54), which improved to a mean of 96 (68 to 100) at the final follow-up. No patient complained of thigh pain at any stage. No acetabular or femoral osteolysis was observed and no hip required revision for aseptic loosening of either component. Deep infection occurred in two hips (0.3%) which required revision. One hip (0.2%) required revision of the acetabular component for recurrent dislocation. Bone mineral densitometry revealed a minimal bone loss in the proximal femur. This cementless anatomical femoral component with metaphyseal loading but without distal fixation produced satisfactory fixation and encourages proximal femoral loading.
We carried out a prospective randomised study designed to compare the penetration rate of acetabular polyethylene inserts of identical design but different levels of cross-linking at a minimum of four years follow-up. A total of 102 patients (102 hips) were randomised to receive either highly cross-linked Durasul, or contemporary Sulene polyethylene inserts at total hip replacement. A single blinded observer used the Martell system to assess penetration of the femoral head. At a mean follow-up of 4.9 years (4.2 to 6.1) the mean femoral head penetration rate was 0.025 mm/year (
We investigated the rate of polyethylene wear of a cementless acetabular component at different periods of follow-up in order to test the hypothesis than an irrecoverable deformation process (creep) was followed by an initially low, but gradually increasing wear rate. We studied prospectively 93 uncemented total hip arthroplasties in 83 patients (mean age 50 years (22 to 63)) with a mean follow-up of 8.2 years (3 to 12). We measured the penetration of the femoral head from radiographs taken immediately after surgery at three, six and nine years, or at the latest follow-up. The median wear rate was 0.17 mm per year in the first three years, a finding which we considered to be caused by creep. Thereafter, the rate of wear declined to 0.07 mm per year (four- to six-year period) and then increased to 0.17 mm per year (seven to nine years) and 0.27 mm per year (more than nine years), which we considered to be a reflection of genuine polyethylene wear. After the nine-year follow-up the wear rates were higher in patients with marked osteolysis. We found no relationship between the inclination angle of the acetabular component or femoral head orientation and the rate of wear. No acetabular component required revision.
